Electroanalytical Characteristics of Lercanidipine and its Voltammetric Determination in Pharmaceuticals and Human Serum on Boron-Doped Diamond Electrode

Boron-Doped Diamond Electrodes: Recent Developments and Advances in View of Electrochemical Drug Sensors

Conductive boron-doped diamond (BDD), in addition to its superior material properties, offers many important advantages that make it an interesting material for electroanalytical studies. It has been considered as an excellent electrode material for electrooxidation of drug active compounds in their dosage forms or in biological materials due to its good physical and chemical properties. It contains not only the largest solvent working potential window compared to other electrode materials, but also it has low background and capacitive currents; lower problems with passivation and it has the ability to withstand extreme potentials, corrosive, and high temperature/pressure environments. The aim of this review is not only to provide a state-of-the-art of diamond electrochemistry but also to serve as a reference point for any researcher wishing to commence work with diamond electrodes and understand electrochemical data. Therefore, it is focused on the carbon-based materials, electrochemical properties of the BDD film electrode, its fundamental research, and its electrochemical pretreatment process are discussed in detail. In this case, there are important studies to show the effective BDD drug sensors for the detection and determination of drugs and the present review critically summarizes the available data in this field between 2015 and 2020.

Calcium channel blocker lercanidipine electrochemistry using a carbon black-modified glassy carbon electrode

Lercanidipine, a third-generation dihydropyridine calcium L-type channel blocker, redox behavior at different carbon electrode materials, in a wide pH range, using cyclic, square-wave, and differential pulse voltammetry, was studied. A comparison was made between unmodified glassy carbon electrode (GCE) and boron-doped diamond electrode (BDDE), and GCE and BDDE modified with a carbon black (CB) nanoparticle embedded within a dihexadecylphosphate (DHP) nanostructured film (CB-DHP/GCE and CB-DHP/BDDE). Lercanidipine oxidation, for 3.4 < pH < 9.5, is an irreversible, diffusion-controlled, pH-dependent process that occurs in two consecutive steps, with the transfer of one electron and one proton, at the N1 and C4 positions in the 1,4-dihydropyridine ring. For pH > 9.5, both oxidation processes are pH-independent and a pKa = 9.40 was determined. Lercanidipine reduction at pH = 7.0 is an irreversible process, and the lercanidipine reduction products are electroactive and follow a reversible electron transfer reaction. Lercanidipine electroanalytical determination, at a nanostructured GCE modified with a CB-DHP film (CB-DHP/GCE), with no need for N2 purging, with a detection limit of 0.058 μM (3.58 × 10^-5 g L^-1) and a quantification limit of 0.176 μM (1.08 × 10^-4 g L^-1), was achieved. Graphical abstract.

Electroanalytical Methods for Determination of Calcium Channel Blockers

Background:

Calcium Channel Blockers (CCBs) are widely used in the treatment of cardiovascular and ischemic heart diseases in recent years. They treat arrhythmias by reducing cardiac cycle contraction and also benefit ischemic heart diseases. Electroanalytical methods are very powerful analytical methods used in the pharmaceutical industry because of the determination of therapeutic agents and/or their metabolites in clinical samples at extremely low concentrations (10-50 ng/ml). The purpose of this review is to gather electroanalytical methods used for the determination of calcium channel blocker drugs in pharmaceutical dosage forms and biological media selected mainly from current articles.

Methods:

This review mainly includes recent determination studies of calcium channel blockers by electroanalytical methods from pharmaceutical dosage forms and biological samples. The studies of calcium channel blockers electroanalytical determination in the literature were reviewed and interpreted.

Results:

There are a lot of studies on amlodipine and nifedipine, but the number of studies on benidipine, cilnidipine, felodipine, isradipine, lercanidipine, lacidipine, levamlodipine, manidipine, nicardipine, nilvadipine, nimodipine, nisoldipine, nitrendipine, diltiazem, and verapamil are limited in the literature. In these studies, DPV and SWV are the most used methods. The other methods were used less for the determination of calcium channel blocker drugs.

Conclusion:

Electroanalytical methods especially voltammetric methods supply reproducible and reliable results for the analysis of the analyte. These methods are simple, more sensitive, rapid and inexpensive compared to the usually used spectroscopic and chromatographic methods.

Determination of lercanidipine in human plasma by an improved UPLC-MS/MS method for a bioequivalence study

An improved and reliable ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated for the determination of lercanidipine in human plasma. Plasma samples with lercanidipine-d3 as an internal standard (IS) were prepared by solid phase extraction on Phenomenex Strata-X cartridges using 100 µL of human plasma. Chromatographic analysis was performed on UPLC BEH C₁₈ (50 mm×2.1 mm, 1.7 µm) column under isocratic conditions. Linear calibration curves were obtained over a wide dynamic concentration range of 0.010-20.0 ng/mL. Matrix effect was assessed by post-column infusion, post-extraction spiking and standard-line slope methods. The mean extraction recovery was >94% for the analyte and IS. Inter-batch and intra-batch precision (% CV) across five quality controls was <5.8%. Bioequivalence study was performed with 36 healthy subjects after oral administration of 10 mg of lercanidipine and the assay reproducibility was evaluated by reanalysis of 133 incurred samples.

Flow injection chemiluminescence determination of lercanidipine based on N-chlorosuccinimide-eosin Y post-chemiluminescence reaction

A novel post-chemiluminescence (PCL) reaction was discovered when lercanidipine was injected into the CL reaction mixture of N-chlorosuccinimide with alkaline eosin Y in the presence of cetyltrimethylammonium bromide (CTAB), where eosin Y was used as the CL reagent and CTAB as the surfactant. Based on this observation, a simple and highly sensitive PCL method combined with a flow injection (FI) technique was developed for the assay of lercanidipine. Under optimum conditions, the CL signal was linearly related to the concentration of lercanidipine in the range 7.0 × 10(-10) to 3.0 × 10(-6)  g/mL with a detection limit of 2.3 × 10(-10) g/mL (3σ). The relative standard deviation (RSD) was 2.1% for 1.0 × 10(-8) g/mL lercanidipine (n = 13). The proposed method had been applied to the estimation of lercanidipine in tablets and human serum samples with satisfactory results. The possible CL mechanism is also discussed briefly.

Electrode mechanism and voltammetric determination of selected guanidino compounds

The present review describes the recent results on the electrochemical activity of bio-guanidino compounds, such as famotidine, metformin, acyclovir, ganciclovir, zanamivir, moroxydine as well as guanidino compounds, such as S-[(2-guanidino-thiazol-4-yl)methyl]isothiourea hydrochloride, 2-guanidino-1,3-thiazole, 2-guanidinobenzimidazole. The focus is on analyzing the electrode mechanism of the guanidino compounds at the hanging mercury drop electrode and at the silver amalgam film electrode, as well as on the character of the square wave (SW) voltammetric signals. It has been stated, that the compounds can act as electrocatalysts — they are protonated and adsorbed at the surface of the electrode, after which the protonated forms of the compounds are irreversibly reduced, yielding their initial form and hydrogen. The experimental adsorption data obtained by measuring the differential capacity of the double layer, the zero charge potential, and the surface tension at the zero charge potential have established the adsorption processes underlying their electrochemical activity. The analytical application of the obtained voltammetric signals in the determination of these compounds in biological samples is also presented. This review concentrates on our own results in the context of general developments in the field.

Assay of lercanidipine hydrochloride in dosage forms using nucleophilic substitution reaction

A simple and sensitive spectrophotometric method has been developed for the assay of lercanidipine hydrochloride (LER) in bulk and in formulations. The method is based on the formation of coloured species between the drug and 1,2-naphthaquinone-4-sulphonic acid sodium salt (NQS) by means of nucleophilic substitution reaction. Absorbance was measured at λ(max) = 460 nm. The method was analyzed statistically. The system obeyed the Beer's law in the range 20-100 μg mL⁻¹. Molar absorptivity value was found to be 4.79 × 10³ L mol⁻¹ cm⁻¹. Limits of detection and quantification were found to be as low as 0.04 and 0.13 μg mL⁻¹. Precision (RSD, 0.4%) and accuracy (recovery 99.2 ± 0.6 to 101.1 ± 0.8%) of the developed method were evaluated.

A Review of Electroanalytical Techniques for Determination of Anti-HIV Drugs

Until now after the human immunodeficiency virus (HIV) was discovered as the then tentative aetiological agent of acquired immune deficiency syndrome (AIDS), exactly 25 anti-HIV compounds have been formally approved for clinical use in the treatment of AIDS. These compounds fall into six categories: nucleoside reverse transcriptase inhibitors (NRTIs: zidovudine, didanosine, zalcitabine, lamivudine, abacavir, stavudine, and emtricitabine), nucleotide reverse transcriptase inhibitors (NtRTIs: tenofovir), nonnucleoside reverse transcriptase inhibitors (NNRTIs: efavirenz, nevirapine, delavirdine, and etravirine), protease inhibitors (PIs: ritonavir, indinavir, saquinavir, nelfinavir, amprenavir, lopinavir, fosamprenavir, atazanavir, tipranavir and darunavir), fusion inhibitors (FIs: enfuvirtide), coreceptor inhibitors (CRIs: maraviroc), and integrase inhibitors (INIs: raltegravir). The present paper submitted the use of various electroanalytical techniques for the determination of anti-HIV drugs. This paper covers the time period from 1990 to 2010 including voltammetric techniques that were reported. Presented application concerns analysis of anti-HIV drugs from pharmaceutical dosage forms and biological samples.